NEW CYCLIC AND POLYMERIC PHOSPHAZENES DERIVED FROM N-SILYLPHOSPHORANIMINES

Silicon-nitrogen-phosphorus compounds of the type Me ₃ SiN═PR(R′)X(X= Cl, Br, OCH₂CF ₃ , OPh), known as N-silylphosphoranimines,are useful precursors to both cyclic and polymeric phosphazenes.Depending on the leaving group (X), thermolysis reactions afford either cyclic trimers, [N═PR(R′)] ₃ (when X = Cl, Br), or linear polymers,[N═PR(R′)]_n (when X = OCH ₂ CF ₃ or OPh). Treatment of the P-trifluoroethoxy and P-phenoxy derivatives, Me ₃ SiN═PR(R′)X (X = OCH ₂ CF ₃ , OPh), with alcohols at lower temperature usually results in the formation of cyclic phosphazene trimers via silyl ether elimination. Recently, we have applied these synthetic methods to the preparation of some new phosphazene systems including a series of 4-aryl-functionalized trimers and polymers and a variety of non-geminal, mixed-substituent cyclic trimers. Representative examples of the synthesis, structural characterization, and reactivity of these new phosphazenes and their Si─N─P precursors are reported here.     

Zum Reaktionsverhalten lithiierter Aminosilane RR′ Si(H)N(Li)SiMe3

The Reaction Behaviour of Lithiated Aminosilanes RR′Si(H)N(Li)SiMe₃ The bis(trimethylsilyl)aminosubstituted silances RR′Si(H)N(SiMe₃)₂ 11 – 16 (R,R′ = Me, Me₃SiNH, (Me₃Si)₂N) are obtained by the reaction of the lithium silylamides RR′Si(H)N(Li)SiMe₃ 1 – 10 (R,R′ = Me₃SiNLi, Me, Me₃SiNH, (M₃Si)₂N) with chlorotrimethylsilane in the polar solvent tetrahydrofurane (THF). In the reaction of the lithium silylamides [(Me₃Si)₂N]₂(Me₃SiNLi)SiH 10 with chlorotrimethylsilane in THF the rearranged product 1,1,3-tris[bis(trimethylsilyl)amino]-3-methyl-1,3-disila-butane [(Me₃Si)₂N]₂Si(H)CH₂SiMe₂N(SiMe₃)₂ 17 is formed. The reaction of the lithium silyamides RR′ Si(H)N(Li)SiMe₃ 1 – 3 (1: R = R′ = Me; 2: R = Me, R′ = Me₃SiNH; 3: R = Me, R′ = Me₃SiNLi) with chlorotrimethylsilane in the nonpolar solvent n-hexane gives the cyclodisilazanes [RR′ Si? NSiMe₃]₂ 18 – 22 (R = Me, Me₃SiNH, (Me₃Si)₂N; R′ = Me, Me₃SiNH, (Me₃Si)₂N, N(SiMe₃)Si · Me(NHSiMe₃)₂) and trimethylsilane. The lithium silylamides 4 , 5 , 6 , 9 , 10 (4: R = R′ = Me₃SiNH; 5: R = Me₃SiNH, R′ = Me₃SiNLi; 6: R = R′ = Me₃SiNLi; 9: R = (Me₃Si)₂N, R ′ = Me₃SiNLi; 10: R = R′ = (Me₃Si)₂N) shows with chlorotrimethylsilane in n-hexane no reaction. The crystal structure of 17 and 21 are reported.     

SYNTHESIS AND NMR CHARACTERIZATION OF P-VINYL SUBSTITUTED PHOSPHAZENE PRECURSORS1

Abstract

The reactions of either PhPCl₂ or PCl₃ with (Me₃Si)₂NLi followed by H₂C[dbnd]CHMgBr were used to prepare the new P-vinyl substituted [bis(trimethylsilyl)amino]phosphines, (Me₃Si)₂NP(R)CH[dbnd]CH₂ [1: R=Ph, 2: CH[dbnd]CH₂, 3: R=Me, and 4: R=N(SiMe₃)₂]. Oxidative bromination of phosphines 3–1 afforded the P-bromo-P-vinyl-N-(trimethylsilyl)phosphoranimines, Me₃SiN[dbnd]P(CH[dbnd]CH₂)(R)Br [5: R=Ph, 6: R=CH[dbnd]CH₂, 7: R=Me], which, upon treatment with CF₃CH₂OH/Et₃N, were subsequently converted to the P-trifluoroethoxy derivatives, Me₃SiN[dbnd]P(CH[dbnd]CH₂)(R)OCH₂CF₃ [8: R=Ph, 9: R=CH[dbnd]CH₂, 10: R=Me]. Compounds 1–10, which are of interest as potential precursors to P-vinyl substituted poly(phosphazenes), were fully characterized by elemental analyses (except for the thermally unstable P-Br derivatives 5–7) and NMR spectroscopy (¹H, ¹³C, and ³¹P) including complete analysis of the vinylic proton splitting patterns via HOM2DJ experiments.     

Lithiumhydridosilylamide R2(H)SiN(Li)R′ – Darstellung,Eigenschaften und Kristallstrukturen

Lithium Hydridosilylamides R₂(H)SiN(Li)R′ – Preparation, Properties, and Crystal Structures The hydridosilylamines R₂(H)SiNHR′ ( 1 a : R = CHMe₂, R′ = SiMe₃; 1 b : R = Ph, R′ = SiMe₃; 1 c : R = CMe₃, R′ = SiMe₃; 1 d : R = R′ = CMe₃) were prepared by coammonolysis of chlorosilanes R₂(H)SiCl with Me₃SiCl ( 1 a , 1 b ) as well as by reaction of (Me₃C)₂(H)SiNHLi with Me₃SiCl ( 1 c ) and Me₃CNHLi with (Me₃C)₂(H)SiCl ( 1 d ). Treatment of 1 a–1 d with n-butyllithium in equimolar ratio in n-hexane resulted in the corresponding lithiumhydridosilylamides R₂(H)SiN(Li)R′ 2 a–2 d , stable in boiling m-xylene. The amines and amides were characterized spectroscopically, and the crystal structures of 2 b–2 d were determined. The comparison of the Si–H stretching vibrations and ²⁹Si–¹H coupling constants indicates that the hydrogen atom of the Si–H group in the amides has a high hydride character. The amides are dimeric in the solid state, forming a planar four-membered Li₂N₂ ring. Strong (Si)H … Li interactions exist in 2 c and 2 d , may be considered as quasi tricyclic dimers. The ‘‘NSiHLi rings”︁”︁ are located on the same side of the central Li₂N₂ ring. In 2 b significant interactions occurs between one lithium atom and the phenyl substituents. Furthermore all three amides show CH₃ … Li contacts.     

Synthesis of Boron–Nitrogen–Phosphorus Compounds from N-Silylphosphoranimines

Two modes of reactivity of N-silylphosphoranimines have been utilized to prepare the title compounds containing either B–N=P or Si–N=P–N–B linkages. First, silicon-nitrogen bond cleavage reactions of the N-silylphosphoranimines, Me₃SiN=PMe(R)OCH₂CF₃ (1: R=Me, 2: R=Ph), with various chloroboranes gave the new N-borylphosphoranimines, Ph(Me₂N)B–N=PMe₂OCH₂CF₃ (2) and [(Me₃Si)₂N](Cl)B–N=PMe₂OCH₂CF₃ (10). In other cases, however, the expected B–N=P products were unstable and cyclic phosphazenes [Me(R)P=N]_3,4 were obtained. Second, deprotonation-substitution reactions of the aminophosphoranimines, Me₃SiN=P(R)Me–N(R)H, were used to prepare a series of novel (borylamino)-phosphoranimines, Me₃SiN=P(R)(Me)–N(R)–B(NMe₂)₂ (18: R=Me, R=t-Bu; 19: R=R=Me; 20: R=Ph, R=t-Bu; 21: R=Ph, R=Me) and Me₃SiN=PMe₂–N(t-Bu)–B(Ph)X (22: X=NMe₂, 23: X=OCH₂CF₃). All of the new boron–nitrogen–phosphorus products were fully characterized by multinuclear NMR (¹H, ¹³C, and ³¹P) spectroscopy and elemental analysis.     

Alternativ-Liganden. XXVI [1]. M(CO)4L-Komplexe (M  Cr,Mo, W) der Chelatliganden Me2ESiMe2(CH2)2E′Me2 (Me  CH3; E  P,As; E′  N,P, As)

Alternative Ligands. XXVI. M(CO)₄ L-Complexes (M ? Cr, Mo, W) of the Chelating Ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ (Me ? CH₃; E ? P, As; E′ ? N, P, As) The reaction of M(CO)₄NBD (NBD = norbornadiene; M ? Cr, Mo, W) with the ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ yields the chelate complexes (CO)₄M[Me₂ESiMe₂]) for E,E′ ? P, As, but not for E and /or E′ ? N. The NSi group is not suited for coordination because of strong (p-d)π-interaction. In the case of the ligands with E ? P or As and E′ ? N chelate complexes can be detected in the reaction mixture, but isolable products are complexes with two ligands coordinated via the E donor group. The new compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations. The spectroscopic data are also used to deduce the coordinating properties of the ligands. X-ray diffraction studies of the molybdenum complexes (CO)₄Mo[Me₂ESiMe₂(CH₂)₂AsMe ₂] (E ? P, As) in accord with the observed coordination effects show only small differences between SiE and CE donor functions. Attempts to use the ligands Me₂ESiMe₂(CH₂)₂AsMe₂ (E ? P, As) for the preparation of Fe(CO)₃L complexes result in the fission of the SiE bonds and the formation of the binuclear systems Fe₂(CO)₆(EMe₂)₂ (E ? P, As) together with the disilane derivative [Me₂Si(CH₂)₂AsMe₂]₂.     

Die Kristallstrukturen der silylierten Phosphanimine Me3SiNP(c-C6H11)3 und (Me3SiNPPh2)2CH2

Crystal Structures of the Silylated Phosphaneimines Me₃SiNP(c-C₆H₁₁)₃ and (Me₃SiNPPh₂)₂CH₂ The crystal structures of Me₃SiNP(c-C₆H₁₁)₃ ( 1 ) and (Me₃SiNPPh₂)₂CH₂ ( 2 ) are determined by X-ray diffraction at single crystals. In both compounds the PN distances correspond to double bonds, the SiN distances to single bonds. With 149.8° the SiNP bond angle in 1 is noticeably large, while it is only 138.5° in 2 , which shows C₂ symmetry. 1 : Space group P2₁/n, Z = 4, lattice dimensions at –70 °C: a = 1143.0(1), b = 1743.0(2), c = 1152.5(1) pm, β = 90.42(1)°; R = 0.0677. 2 : Space group I4₁/a, Z = 8, lattice dimensions at –60 °C: a = b = 1959.7(1), c = 1695.8(1) pm, R = 0.0433.     

Zur Reaktion von Fluorphosphanen mit Silylaziden

On the Reaction of Fluorophosphanes with Silylazides . The fluorophosphanes Ph₂PF ( 1 ), PhOPF₂ ( 2 ), C₅H₁₀NPF₂ ( 3 ), (Et₂N)PF₂ ( 4 ), and (Et₂N)₂PF ( 5 ) react with Me₃SiN₃ via azidophosphanes R_3?nP(N₃)_n to oligo- and polyphosphazenes, (RR′P?N)_n. (ⁱPr₂N)₂PF ( 6 ), however, is oxidized by Me₃SiN₃ yielding the N-silylated phosphazene (ⁱPr₂N)₂PF?N? SiMe₃ ( 7 ). ^tBuPh₂SiN₃ is considerably less reactive. On contrary to Me₃SiN₃ it even oxidizes 5 and 1 forming (Et₂N)₂FP?N? SiPh₂^tBu ( 10 ) and Ph₂FP?N? SiPh₂^tBu, resp.     

Phosphaniminato-Trichloroselenate(II): Synthese und Kristallstrukturen von [SeCl(NPPh3)2]+SeCl3− und [Me3SiN(H)PMe3]2+[Se2Cl6]2−

Phosphorane Iminato-Trichloroselenates(II): Syntheses and Crystal Structures of [SeCl(NPPh₃)₂]⁺SeCl₃^? and [Me₃SiN(H)PMe₃]₂⁺[Se₂Cl₆]^2? [SeCl(NPPh₃)₂]⁺SeCl₃^? has been synthesized by the reaction of Se₂Cl₂ with Me₃SiNPPh₃ in acetonitrile solution, forming orangered crystals, whereas red crystals of [Me₃SiN(H)PMe₃]₂⁺[Se₂Cl₆]^2? were obtained by the reaction of Me₃SiNPMe₃ with SeOCl₂ in acetonitrile solution. Both complexes were characterized by X-ray structure determinations. [SeCl(NPPh₃)₂]⁺SeCl₃^?: Space group P2₁/n, Z = 4, structure solution with 7 489 observed unique reflections, R = 0.057. Lattice dimensions at ?60°C: a = 1 117.0; b = 2 241, c = 1 407.5 pm, β = 95.61°. In the cation [SeCl(NPPh₃)₂]⁺ the selenium atom is φ-tetrahedrally coordinated by the chlorine atom and by the nitrogen atoms of the phosphorane iminato ligands, whereas the anion SeCl₃^? has a T-shaped structure with φ-trigonal-bipyramidale surrounding of the selenium atom. [Me₃SiN(H)PMe₃]₂⁺[Se₂Cl₆]^2?: Space group P2₁/c, Z = 4, structure solution with 2 093 observed unique reflections, R = 0.080. Lattice dimensions at ?70°C: a = 956, b = 828, c = 1 973 pm, β = 93.80°. The structure consists of [Me₃SiN(H)PMe₃]⁺ ions and planar [Se₂Cl₆]^2? anions, in which the selenium atoms are bridged nearly symmetrically by two chlorine atoms.     

Alternativ-Liganden. XXV. Neue Chelatliganden des Typs Me2ESiMe2(CH2)2E′Me2 (E=P,As; E′=N,P, As)

Alternative Ligands. XXV. New Chelating Ligands of the Type Me₂ESiMe₂(CH₂)₂E′Me₂ (E=P, As; E′=N, P, As) Chelating ligands of the type Me₂EsiMe₂(CH₂)₂E′ Me₂, have been prepared by the following routes: Starting from Me₂Si(Vi)Cl, the compounds with E=N and E′ =N ( 1 ), P ( 2 ), As ( 3 ) are obtained in yields of 65 to 78% by aminolysis to yield Me₂NSiMe₂Vi, followed by the LiE′ Me₂ catalyzed addition of He′Me₂ to the vinyl group. The intermediates ClSiMe₂(CH₂)E′Me₂ [E′=N ( 4 ), P ( 5 ), As ( 6 )] are produced by the reactions of 1 to 3 with PhPCl₂. 5 and 6 can be prepared in a purer form by the photochemical addition of HPMe₂ and HAsMe₂, respectively, to the vinyl group of Me₂Si(Vo)Cl. 4 to 6 react with LiEMe₂, in situ prepared from n-BuLi and HEMe₂, to yield the ligands Me₂ESiMe₂(CH₂)₂E′Me₂ ( 7–12 ) (E=P, As; E′=N, P, As). The new compounds have been characterized by analytical and spectroscopic investigations (NMR, MS).     

Reaktionen silylierter Phosphanimine mit Iodmonochlorid und Iodtrichlorid. Die Kristallstrukturen von [Me3SiNPMe3 · ICl], [Ph3PNCl · ICl] und [Me3PN(H)PMe3] [ICl2]2

Reactions of Silylated Phosphorane Imines with Iodine Monochloride and Iodine Trichloride. The Crystal Structures of [Me₃SiNPMe₃ · ICl], [Ph₃PNCl · ICl], and [Me₃PN(H)PMe₃][ICl₂]₂ The donor-acceptor complex [Me₃SiNPMe₃ · ICl] has been prepared from Me₃SiNPMe₃ and ICl in acetonitrile solution forming yellow-orange crystals. [Ph₃PNCl · ICl] can be prepared by the reaction of Me₃SiNPPh₃ with ICl₃ in dichloromethane solution forming pale yellow crystals. [Me₃PN(H)PMe₃][ICl₂]₂ is formed in a small amount by a slow reaction of Me₃SiNPMe₃ with ICl₃ in CCl₄ suspension in the presence of traces of moisture. All samples are characterized by IR spectroscopy and by X-ray structure analyses. [Me₃SiNPMe₃ · ICl] (1) : Space group Iba2, Z = 8, structure solution with 1 727 observed unique reflections, R = 0.051. Lattice dimensions at ?60°C: a = 1 510.7, b = 1 862.8, c = 988.9 pm. 1 has a molecular structure in which the N atom of the phosphorane imine is connected with the iodine atom of the ICl molecule in a linear arrangement N? I? Cl. Bond lengths N? I = 222.7 pm, I? Cl = 265.1 pm. [Ph₃PNCl · ICl] (2) : Space group Pna2₁, Z = 4, structure solution with 1 530 observed unique reflections, R = 0.030. Lattice dimensions at 20°C: a = 1 522.8, b = 1 408.3, c = 865.8 pm. 2 has a molecular structure in which the N atom of the N chlorophosphorane imine is connected with the iodine atom of the ICl molecule in a linear arrangement. Bond lengths N? Cl = 174.4 pm, N? I = 229.5 pm, I? Cl = 251.2 pm. [Me₃PN(H)PMe₃][ICl₂]₂ (3) : Space group P2₁/c, Z = 4, structure solution with 1 989 observed unique reflections, R = 0.029. Lattice dimensions at ?50°C: a = 1 223.1, b = 1 090.2, c = 1 482.8 pm, β = 112.21°. 3 consists of [Me₃PN(H)PMe₃]²⁺ ions and ICl₂^? anions. The PNP bond angle of the dication amounts to 134.4° with PN distances of 165.6 and 166.1 pm, approximately according to double bonds.     

α-Metallated vinyl carbanionoids: III. Reactions of α-triorganostannylvinyllithiums with group IVB organometallic halides: Formation of α-trimethylplumbylvinyllithiums

Reactions of α-stannylvinyllithiums RR′CC(Li)SnMe₃ with halides Me₃MCl (M = Si, Ge, Pb) give the corresponding mixed bis(trimethylmetal)alkenes RR′CC(SnMe₃)₃. With two equivalents of methyllithium and trimethyllead chloride, RR′CC(SnMe₃)₂ can be converted to RR′CC(PbMe₃)₂. The latter, as well as RR′CC(SnMe₃)PbMe₃, undergoes transmetallation with methyllithium to give α-plumbylvinyllithiums RR′CC(Li)PbMe₃ which are more stable and apparently less basic than the corresponding α-stannyl anions.Multinuclear NMR data for the anionic species are presented and discussed.     

Some addition reactions of bisgermavinylidene

The reaction of bisgermavinylidene [(Me₃SiN?PPh₂)₂C?Ge→Ge?C(PPh₂?NSiMe₃)₂] ( 1 ) with AdNCO (Ad = Adamantyl) afforded the [2 + 2] cycloadditon product [(Me₃SiN?PPh₂)₂CGeC(O) NAd] ( 2 ). Similar reaction of 1 with Ph₃SiOH in tetrahydrofuran (THF) yielded the base‐stabilized germanium(II) triphenylsiloxide [H₂C(PPh₂?NSiMe₃)₂Ge(OSiPh₃)₂] ( 3 ). The results suggested that reactive germavinylidene may exist in solution and is capable of forming addition reaction products. The X‐ray structures of 2 and 3 were determined. Copyright © 2007 John Wiley & Sons, Ltd.     

Diamino-di-tert-butylsilane als Bausteine cyclischer (SiN)2−, (SiNBN)2−, (SiN2Sn)- und spirocyclischer (SiN2)2Si-, (SiN2Sn)2S-Verbindungen

Diamino-di-tert-butylsilanes - Building Blocks for Cyclic (SiN)₂, (SiNBN)₂, (SiN₂Sn), and Spirocyclic (SiN₂)₂Si, (SiN₂Sn)₂S Compounds The aminochlorosilanes (Me₃C)₂SiClNHR ( 1 : R?H, 2 : R?Me) are obtained by the ammonolysis ( 1 ) respectively aminolysis ( 2 ) of di-tert-butyldichlorosilane in the n-hexane. The dilithium derivative of diamino-di-tert-butylsilane reacts with FSiMe₂R′ ( 3 : R′?Me, 4 : R′?F) in a molar ratio 1 : 2 to give the 1,3,5-trisilazanes 3 and 4 , (Me₃C)₂SiNHSiMe₂R′, in a molar ratio 1 : 1 with F₃SiN(SiMe₃)₂ to give the 1,3-diaza-2,4-disilacyclobutane 5 , (Me₃C)₂Si(NH)₂SiFN(SiMe₃)₂, and with F₂BN(SiMe₃)₂ to give the 1,3,5,7-tetraaza-2,6-dibora-4,8-disilacyclooctane 6 , [(Me₃C)₂SiNH-BN(SiMe₃)₂-NH]₂. The dilithium derivative of di-tert-butyl-bis(methylamino)silane reacts with SiF₄ with formation of the 1,3,5-trisilazane 7 , (Me₃C)₂Si(NMeSiF₃)₂, and the spirocycic compound 8 , [(Me₃C)₂Si(NMe)₂]₂Si, with SnCl₂ the cyclosilazane 9 , (Me₃C)₂SiNMe₂ is obtained. The dilithium derivative of 3 reacts with SnCl₂ to give the cyclo-1,3-diaza-2-sila-4-stannylen 10 , (Me₃C)₂Si(NSiMe₃)₂Sn. The oxidation of 10 with elemental sulfur leads to the formation of the spirocyclus 11 , [(Me₃C)₂Si(NSiMe₃)₂SnS]₂.     

Chemie der Phosphorfluoride. XL. Über Phosphazene vom Typ RF2PN?PF2 und ihre Tetracarbonylmolybdänkomplexe

Chemistry of Phosphorus Fluorides. XL. Phosphazenes of the Type RF₂P?N? PF₂ and their Tetracarbonvlmolybdenum Complexes Reaction of Fluorophosphorances, RPF₄ (R = F, Ph), with bis(trimethylsilyl)-aminodifluorophosphine, (Me₃Si)₂N · PF₂, gives rise to cleavage of the Si-N bond in the latter and phosphazenes of the type, RF₂P?N? PF₂, are formed. Displacement of the coordinated cycloolefin with formation of cis-(RF₂P?N? PF₂)₂Mo(CO)₄ occurs upon reaction of C₇H₈Mo(CO)₄ (C₇H₈ = bicycloheptadiene) with RF₂P?N? PF₂. A complex, cis-[(Me₃Si)₂N · PF₂]₂Mo(CO)₄ has also been obtained. Characterization of the compounds was by i.r., mass, ¹⁹F, and ³¹P n.m.r. spectroscopy.     

Metastable P-Tellurium-Substituted Phosphaalkenes: Formation, 125Te- and 31P-NMR Spectroscopic Characterization,and Decomposition

Abstract

The formation and decomposition of P-tellurium-substituted phosphaalkenes was followed by ³¹P- and ¹²⁵Te-NMR spectroscopy. Acyclic compounds with C?P-Te moieties are in general thermally labile, but bulky substituents enhance the lifetime of a number of species. The P-chlorophosphaalkene (Me₃Si)₂C?PCl (1a) reacts with the disilyltelluride (iPrMe₂Si)₂Te (2) leading to the mixed-substituted telluride (Me₃Si)₂C?PTeSiMe₂iPr 3a which reacts with another equivalent of 1a furnishing the tellurobis(phosphaalkene) [(Me₃Si)₂C?P]₂Te (4a). 4a is a shortlived compound decomposing thermally with precipitation of elemental tellurium, leading to a known diphosphabicyclobutane 5a. In a similar way, the bulkier P-chlorophosphaalkene (iPrMe₂Si)₂C?PCl (1b) reacts with (iPrMe₃Si)₂Te furnishing [(iPrMe₂Si)₂C?P]₂Te (4b), which loses tellurium much more slowly than 4a and can be kept in cold solutions for an extended time. Reactions of in situ-prepared lithium aryltellurolates LiTeAr 6 – 9 [Ar?Ph: 6, Ar?2,4,6-Me₃Ph (?Mes): 7, Ar?2,4,6-iPr₃Ph (?TIP): 8, Ar?2,4,6-tBu₃Ph (?Mes*): 9] with 1a provide P-aryltellurophosphaalkenes 10 – 13, which decompose with the loss of diarylditellurides leading to 5a. After a 2 + 4 cycloaddition trapping experiment of 12 with cyclopentadiene, a metastable P-aryltelluro phosphanorbornene 14 was detected by ³¹P-NMR. Reactions of elemental tellurium with P-phosphanylphosphaalkenes (Me₃Si)₂C?PPR′R′;′ 15 – 17 (R′, R′′?iPr: 15; R′?iPr, R′′?tBu: 16; R′, R′′?tBu: 17) lead to metastable insertion products (Me₃Si)₂C?PTePR′R′′ 18 – 20 that decompose with formation of the tellurobisphosphanes (R′R′′P)₂Te 21 – 23, and of the bicyclic diphosphane 5a, which isomerises thermally to the diphosphabicyclooctane 24. The P-di-i-propylphosphanyl-phosphanorbornene 25 dismutates under the action of tellurium into the symmetric diphosphanes iPr₄P₂ and bis-phosphanorbornene 26. The tellurium-free products 24 and 26 were characterized by X-ray crystallography.     

Reaktionen von Silylphosphanen mit Schwefel

Reactions of Silylphosphines with Sulphur We report about reactions of Me₂P? SiMe₃ 2 , MeP(SiMe₃)₂ 3 , (Me₃Si)₃P 4 , P₂(SiMe₃)₄ 5 , and (Me₃Si)₃P₇ 1 with elemental sulphur. Without using a solvent 2 reacts very vigorously. The reactions with 3 and 4 show less reactivity which is even more reduced with 5 and 1 . With equivalent amounts of sulphur the reactions with 2 , 3 , 4 lead to compounds with highest content of sulphur. These compounds are Me₃SiS? P(S)Me₂ 9 from 2 , (Me₃SiS)₂P(S)Me 13 from 3 and (Me₃SiS)₃P(S) 16 from 4 . Besides, the by-products (Me₃Si)₂S 8 , P₂Me₄ 7 , and Me₂P(S)? P(S)Me₂ 11 can be obtained. The reactions of silylphosphines in a pentane solution run much slower so that the formation of intermediates can be observed. Reaction with 2 yields Me₃SiS? PMe₂ 6 and Me₂P(S)PMe₂ 10 , which lead to the final products in a further reaction with sulphur. From 3 (Me₃SiS)(Me₃Si)PMe 14 and (Me₃SiS)₂PMe 12 can be obtained which react with sulphur to (Me₃SiS)₂P(S)Me 13. 4 leads to the intermediates (Me₃SiS)(Me₃Si)₂P 18 , (Me₃SiS)₂(Me₃Si)P 17 , (Me₃SiS)₃P 15 yielding (Me₃SiS)₃P(S) 16 with excess sulphur. Depending on the molar ratio (P₂SiMe₃)₄ 5 reacts to (Me₃Si)₂P? P(SSiMe₃)(Sime₃), (Me₃SiS)(Me₃Si)P? P(SSiMe₃). (Diastereoisomer ratio 10:1), (Me₃SiS)₂P? P(SiMe₃)₂ and (Me₃SiS)₂P? P(SSiMe₃)(Sime₃). With the molar ratio 1:4 the reaction yields (Me₃SiS)₂P? P(SSiMe₃)₂ (main product), (Me₃SiS)₃P(S) and (Me₃SiS)₃P. All silylated silylphosphines tend to decompose under formation of (Me₃Si)₂S. (Me₃Si)₃P₇ reacts with sulphur at 20°C (15 h) under decomposition of the P₇-cage and formation of (Me₃SiS)₃P(S). The products of the reaction of 5 with sulphur in hexane solution (molar ratio more than 1:3) undergo readily further reactions at 60°C under cleavage of P? P bonds and splitting off (Me₃Si)₂S, leading to (Me₃SiS)₃P(S) and cage molecules like P₄S₃, P₄S₇, and P₄S₁₀ and P? S-polymers. (Me₃SiS)₃P(S) isi thermally unstable and decomposes to P₄S₁₀ and (Me₃Si)₂S. Sulphur-containing silylphosphines like (Me₃SiS)P(S)Me₂ react with HBr at ?78°C under formation of Me₃SiBr (quantitative cleavage of the Si? S bond) and Me₂P(S)SH, which reacts with HBr to produce H₂S and Me₂P(S)Br.     

EQUILIBRIUM STUDIES OF THE REACTION BETWEEN TETRACHLOROPALLADIUM(II) ANION AND SULFOXIDES. THE FORMATION OF THE MONO-S-SULFOXIDE COMPLEXES

Abstract

The equilibrium coefficient, K₁, for the reaction [PdCl₄]^2- + RR′ SO ? [Pd(RR′ SO)Cl]^? + Cl^?, has been determined for dimethylsulfoxide, tetramethylensulfoxide, and phenylmethylsulfoxide and found to be 67, 46 and 8.8 respectively at 25°C, ü= 1.0 in 95:5 methanol-water. Values for the equilibrium constants for the dimethylsulfoxide complex are also reported at other ionic strengths. The equilibrium constants for the second stage, [Pd(Me₂SO)Cl₃]- + Me₂SO)?-[Pd(Me₂SO)₂Cl₂] + Cl^?, has been determined for dimethylsulfoxide only, K₂=2.5 × 10^?2 at 25°C (μ not controlled). The causes of the mutual destabilisation of two dimethylsulfoxides are discussed.     

Bildung und Reaktionen silylierter Diphosphane

Preparation and Reactions of Silylated Diphosphanes The preparation of previously not available silylated diphosphanes is reported, i. e. the compounds (Me₃Si)₂P? P(SiMe₃)(CMe₃) 1 , (Me₃Si)₂P? P(CMe₃)₂ 2 and (CMe₃)₂P? P(SiMe₃)(CMe₃) 4 as well as of the respective PH containing derivatives and Li phosphides thereof. The reaction of 1 with MeOH leads to (Me₃Si)₂P? P(CMe₃) H 6 , while 4 generates (Me₃C)₂P? P(CMe₃) H 7 , and finally 3 gives access to (Me₃C)(Me₃Si)P? P(CMe₃) H 8 . LiBu on the other hand forms the Li phosphides Li(Me₃Si)P? P(SiMe₃)(CMe₃) 10 (through 1 ), Li(Me₃Si)P? P(CMe₃)₂ 11 (through 2 ), Li(Me₃C)P? P(SiMe₃)(CMe₃) 12 (through 3 ), and Li(Me₃C)P? P(CMe₃)₂ 13 (through 4 ), the latter being more easily accessible through the reaction of H(Me₃C)P? P(CMe₃)₂ with LiBu. The introduction of one single CMe₃ substituent into 1 is sufficient to obtain the Li phosphide 10 , which is stable in ethers, as opposed to the corresponding Li Phosphide of the persilylated diphosphane.